Receiving station



L. M. CLEMENT.

RECEIVING STATION.

nPPLIcATloN FILED MAR. 22. ma.

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l L. M. CLEMENT.

RECEIVING STATION.

APPLICATION FILED MAR. 22. I9l8 Patente May 16, 1922.

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LEWIS M. CLEMENT, 0F I\]'E`\7ARK,A NEW JERSEY, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, IIICORPORATED, 0F NEW YORK, N. Y., A CORPORATION OF NEW YORK.

RECEIVING STATION.

Specification of Letters Patent.'

Patented May 16, 1922.

Application filed March 22, 1918.- Serial No. 223,918.

To all whom t may concern Be it known that I, LEWIS M. CLEMENT, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Receiving Stations, of which the following is a full, clear, concise, and exact description.

This invention relates to electromagnetic wave receiving stations,

An object of the invention is to produce a receiving station capable of receiving many kinds of signals efficiently, and particularly one in which a detector circuit may act to detect waves of one or more kinds and also in combination with another or other detecting circuit arrangements may detect waves having one or more different characteristics.

A more specific object is to produce a station in which a single detector circuit may receive simple damped wave trains of long or short wave length and sustained oscillations of long or short wave length, and also may act as one of a set of detectors to detect plurally modulated or modified waves.

A further object is to produce a system of circuits which may be rapidly and conveniently tuned to receive plurally or successively modulated or modified waves.

A still further object is to produce a system capable of receiving signaling waves in a plurality of different ways and which may be rapidly and readily changed from a condition adapted to one method of reception to a condition adapted to another method of reception.

In the accompanying drawings Fig. 1 represents one form of the invention, and Fig. 2 a modified form of the part between the dotted lines X-X of Fig. 1 which may be substituted.

Referring to Fig. 1, the numeral 1 represents an antenna circuit containing adjustable capacity 2, coil 3, the antenna being grounded at G. To the ground is attached a conductor 4 forming a common ground for the whole system. Coil 3 is variably coupled to coil 5, both of which are of variable inductance and preferably movable with re- Y* spect to each other. The upper end of coil 3 and lower end of coil 5 represent portions which may act to increase the inductance 0f their respective circuits but have substantially no coupling with other coils. Condenser 6 is in circuit with coil 5 whose terminals are across the input of detector tube D, the path to the filament of tube D being through ground connection 4. Capacities 2 and 6 and coils 3 and 5 represent any. suitable means which may be variable over wide ranges, so that the antenna and circuit 5, 6 are capable of being tuned to frequencies varying from 20,000 or less to 1,000,000 or more. When switch 8 is on contact I), the output circuit of detector D extends from the plate through feed-back coil 7, which is variably coupled to coil 5, thence to doublethrow switch 9. If switch 9 is in the up position, the path extends on through conductor 10 to switch 11. If switch 11 is in the up position, the path continues through conductor 12, coil 13, generator or battery E3 and ground line 4, back to the filament of tube D. Variations of current in coil 13 are impressed upon coil 14 and by means of adjustable resistance 15, which forms a potentiometer, are impressed upon the gridfilament or input circuit of amplifying tube A. In the output of A is a receiver 16.

If greater amplification is desired, switch 11 can be thrown down and the coil 17 will be in the output of detector D and the variations will be impressed upon amplifier A through coil 18. Tube A will in this case impress its output on tube A for further amplification.

In receiving plurally modulated waves and other waves such as are employed for signaling, it is frequently desirable that the received waves be detected two or more times in succession in order to secure a high degree of selectivity and thereby discriminate against undesired waves in favor of desired waves. In receiving successively modulated waves, one desirable mode of reception con sists in detecting a number of times equal in number to the successive steps of modulation.

In the particular embodiments of the invention shown, arrangement is made for double detection, or detection in two stages. Switch 8 is preferably placed on contact a. Switch 9 is down and the output of de- 1tector D is impressed upon the circuit consisting of capacity 19, inductance coil 2O and variable inductance coil 21, which may be cut out if desired. Capacity 19 acts as a high frequency leak. Coil Q is coupled to coil 2:2 which is in circuit with capacity 23 and coil 24, which coil may be adjusted to zero if desired. The terminals of capacity 23 are connected respectively to grid and filament of detecting tube D, the latter connection being through conductor and ground conductor el. In the output of tube D is placed feed-back coil 26, adjustably coupled to coil 22. The output circuit also includes conductor 2T, switch 9 and conductor 10. If switch 11 is up, the output will be impressed upon tube A and amplified. If switch 11 is down, the input will be impressed upon tube A and amplified by tubes A and A in two stages.

When switch S is on contact Z), the variable capacity 28 is across the output of detector D and acts as a leak for high frequency. The feed-back coil 7 is then operative, but it may be adjusted to Zero coupling if desired. lVhen switch 8 is on contact a., the feed-back coil 7 is short-circuited and the circuit of capacity Q8 is open. Batteries El, E2, E, furnish plate current for the tubes with which they are connected at any time and EI furnishes current to heat all the filaments.

It is not an essential part of the invention that the second detector D have a feed-back coil and act as an oscillator. It may have the output of an independent oscillator applied thereto as in Fig. Q which represents an alternative form for the parts of Fig. 1 which are between lines X-X. In Fig. 2 the parts designated by the same numerals as in Fig. 1 are similar and perform the same function. Coil 24: is intercoupled with coil 3Q in an inductive circuit 32,33, 34. Vacuum tube O and its associated circuits constitute an oscillator. Its frequency is determined by capacity and inductances 3G and 37. The battery E, supplies output current to this tube and the filament is heated by source Ef. Coil 36 is coupled to coil 3a, whence energy is fed into the circuit 22, 23 which forms the input circuit of detector D. In this manner the frequency of oscillator D can be set at such value as to give a suitable beat note with the detected signals.

Operation: To receive damped wave trains of high or moderate radio frequencies, the antenna 1 and circuit 5, 6 are properly timed, switch 8 is put into position a., switch 9 is placed up and switch 11 may be up or down, depending on whether single or double amplification is desired. F or continuous waves switch S is placed upon position Z) and the coupling of coil 7 and capacity 28 are adjusted. This causes detector D to act also as an oscillator when elements 2, 3, 5

and G and the intercouplings of coils 3, 5 and 5, 7 are properly adjusted. By suitable adjustments the frequency and intensity of the beat note may be varied. Switch 9 remains as before and switch 11 may be in either position, depending upon whether single or double amplification is desired.

Suppose now that it is desired to receive messages sent by certain kinds of doubly modulated waves. The input circuits 0f the first detector D must be attuned to the high frequency and the input circuits of the second detector D must be attuned to the intermediate frequency. Tt has been found that if a telephone is placed across the output of a detector which operates to receive the high frequency, it will give a certain imperfect signal. In almost any instance some kind of an indication will be produced if the frequency generated by the first self-oscillating detector D is such as to give a beat note having a frequency within the audible range. This is taken advantage of by listening at receiver 1G and timing the antenna and input circuit of detector D as for continuous singly modulated oscillations in the manner hereinbefore described. Switch 9 is then thrown down, switch 8 is thrown to position a, and circuits containing elements 19, 20, 22 and 23 are adjusted to resonance to the intermediate frequency. For heterodyne receiving, the coupling of coil 26 may be varied until a suitable beat note is received. By means of switch 11 single or double stage amplification may be had.

The arrangement shown is adapted for a wide variety of uses as a receiving station, and particularly as a receiver of plurally modulated waves, since means is provided in such case to enable the operator to determine when the proper circuits of the station are properly tuned to the highest frequency and subsequently without disturbing this arrangement to switch to an arrangement in which proper circuits may be tuned to the intermediate frequency. This apparatus may also be used either for telegraphy or telephony to receive on the so-called homodyne or zero beat frequency principle.

lVhile only two specific forms of the in` vention have been described, the appended claims are intended to cover the novel features of the invention both broadly and specifically.

That is claimed is:

1. In a signal receiving station, a detector, a receiving instrument, associated means whereby simple wave trains are applied by said detector to said instrument, and means including a. portion of said first named means whereby plurally detected waves may be applied to said instrument.

2. In a signal receiving station, a detecting means, a receiving instrument, a switching means, and a second detecting means,

said switching means being capable of switching said first mentioned detector into operative relation with said receiving instrument or with said second detecting means.

3. In a signal receiving station, a plurality of detectors, means capable of relating` said detectors in tandem connection, each said detector having a feed-backy connection, and means for utilizing less than the whole number of said detectors to detect waves received at said station.

4. In a signal receiving station, a plurality of detectors arranged in tandem, each of said detectors having a local oscillation producing means connected therewith, and means comprising a switching arrangement for connecting into circuit and utilizing less than the whole number of said detectors to produce audible indications from received waves.

5. In a signal receiving station, a plurality of detectors arranged in tandem, an input circuit for each of said detectors, means for feeding locally generated waves into said input circuits, and a switch for throwing one of said detectors out of circuit and leaving the remainder thereof connected in circuit. 6. In a signal receiving station, a plurality of detectors, means capable of relating said detectors in tandem relation, a regenerative feed-back connection for each detector, and means operated by a single operative movement for removing from said tandem relation at least one of said detectors and leaving the remainder thereof in operative relation.

7. In combination, a plurality of means for successive detection of signal waves, and other means whereby one of said means may be used without the other of said means to detect signal waves.

8. In combination, a plurality of means for successive detection of signal waves, other means whereby one of said means may be used without the other of said means to detect signal waves, and signal indicating means common to said one means and to said plurality of means.

9. In a signal receiving station, a detecting means and indicating means for indicating signals detected by said detecting means, and another means which upon operation interposes a second detecting means between said first mentioned detecting means and said indicating means.

10. In a signal receiving station, a plurality of detecting means, an indicating means, and a single switch which is capable of alternatively associating one or a plurality of said detecting means and said indicating means in tandem connection.

11. In a signal receiving station, a vacuum tube detector, a feed-back connection therefor whereby said detector may oscillate with a period diering from that of received sig-` nals, a receiver for indicating the resulting beats, and means for interposing a second detector between said first detector and said receiver.

12. In a signal receiving station, a vacuum tube detector, a feed-back means therefor, a receiver operatively associated with said detector, means for interposing a second detector between said first detector and said receiver, and means for rendering inactive sa'tl feed-back means. l/LB. A signal receiving station including a receiving conductor, a thermionic detector into which the energy existing in said conductor is fed, a second detector into which the output of said first detector is fed, means for supplying locally generated oscillations to said second detector, and a signal indicating means adapted to be affected by energy existing in the output circuit of said second detector.

14. In a signal receiving system, a plurality of detector circuit arrangements, at least one of which is adapted to function without all of the others as a detecting means for waves of certain characteristics and which is incapable of efliciently functioning as a detecting means for waves of certain other characteristics, but which is capable of acting with other of said detecting arrangements to efficiently detect said waves of other characteristics, and means for associating said detector circuit arrangements to enable them to so function.

15. In a signal receiving station, a plurality of wave distorting devices arranged in tandem, an input circuit for each of said devices, means for feeding locally generated waves into said input circuits, means for eliminating one of said devices from circuit, and means operated by the action of said second mentioned means for causing one of said devices to remain in operative relation.

16. In a signal receiving system, a plurality of wave distorting devices, means capable of relating said devices in tandem relation, a regenerative feed-back connection for each device, and means for removing from circuit one of said devices other than the irst thereof and consequently leaving the remainder thereof in operative relation.

17. A system comprising a plurality of thermionic repeaters in tandem, means operable to supply oscillations of a locally predetermined nature to each of said repeaters, a receiving conductor, a translating device, and switching arrangements capable of connecting a plurality of said repeaters in operative tandem relation between said conductor and said translating ldevice and alternatively capable of connecting a smaller number of said repeaters in operative relation between said receiving conductor and said translating device.

'18. A system comprising a plurality of immessa Wave distorting devices in tandem relation, tive relation to the remainder thereof and means connected to a plurality of said desimultaneously connecting the remainder of vices for supplying locally generated Waves said devices into an operative system. l0 to said devices respectively, means for chang- In witness whereof, I hereunto subscribe ing the frequency of at least one of said my name this fourteenth day of March locally generated Waves, and means for re- A. D., 1918.

moving one o said devices from its opera- LEWIS M. CLEMENT. 

